In the lead up to the Avengers, we knew Loki was going to be the villain, especially in the "Thor" end credit scene... Marvel has been known for after credit scenes to hint at next possible movie plots. But so far the end credit for Ironman 3 provided no hints for "Avengers 2" and "Thor 2" end credit scene hinted at "Guardians of the Galaxy". In the upcoming Marvel movies, when do you think Ultron will be introduced and how?...